Floor nailing machine



D. J. DOUGHERTY 2,457,984

FLOOR NAILING MACHINE Jan. 4, 1949.

Filed Au 21, 1945 s Sheets-Sheet 1' Q B. x s

IN V EN T 0R. .04N/EL J 0006/15? BY 7 3 VQPMM Jan. 4, 1949. D. J. DOUGHERI'Y 2,457,984 moon NAILING momma Filed Aug. 21, 1945 s Sheets-Sheet 2 INVENTOR. flew/1 J Dow/153W Jan. 4, 1949. D. J. DOUGHERTY FLOOR NAILING MACHINE 5 Sheets-Shee t 5 Filed Aug. 21, 1945 IN V EN T OR. 04mm 000mm 7j BY .Jan. 4, 1949. D. J. DOUGHERTY FLOOR NAILING MACHINE 5 Sheets-Sheet 4 Filed Aug. 21, 1945 INVENTOR. D

DEN/EL J. OUGHEQTY Jan. 4, 1949.

D. J. DOUGHERTY 2,457,984

FLOOR NAILING MACHINE Filed Aug. 21, 1945 5 Sheets-Sheet 5 INVENTOR. D/l/V/[L J. Doug/45hr Patented Jan. 4, 1949 UNITED {STATES PATENT O F F ICE r FLOOR NAILINGMACHINE. Daniel J. Daughert Snohomish, Wash.,assignor of forty-nine one hnndredths to Oscar ,A.

Gregorson, Seattle, Wash;

Application August 21, 1945, Serial No. 611,826

6 Claims.

This invention relates to improvements in floor nailing machines, and it has reference more particularly to machines for nailing Wood floors that "are made of boardsvvithout the usual tongue and groove edges and which boards are laid edge to edge and nailed straight through from the top such flooring usually being of hardwood and comprising boards from one-quarter to one-half inch thick and from one and one-half to three inches Wide, and which, preparatory to final nail:

ing, are put in place over the area to be floored,

then wedged tightly tog-ether and held for final nailing.

It is the principal object of this invention to provide a nail driving machine that will operate automatic-ally, after being initially placed in position and started, to travel across the prepared area, and to quickly and uniformly drive a row of nails; .each board receiving a nail therethrough closely adjacent each of its opposite side edges or at designated intervals that best suit the particular floor being laid.

Another object of the invention is to provide for the advancement of the machine by intermittent movements and toeffect the driving of the nails during the pe'rio'ds of rest. Furthermore, to provide means for advancing the machine, after each nail is driven, that certain dis-- tance required to properly locate it for the next driving operation, Whether .theadvanc'e be relatively long as across a board, or relatively short, as when advancing from the edge of one board to the adjacent edge of the next board.

Still another object of the invention is to provide a machine of the above stated kind that will advance straight across a floor area, and

wherein a novel stopdevice is provided to engage a Wall or stopping abutment to actuate the said stop .device to release the driving clutch of the machine after the machine has traversed an area, so that it may beieversed and again started across the area.

Still further objects of the invention reside in the details of construction of the various parts, in their combination, and in their relationship and mode of operation as will hereinafter be fully described.

In accomplishing th above :mentioned and other objects of the invention, I haveprovided the improved details of construction, the preferred forms ,of which are illustrated in the accompanyingdrawings, wherein- Fig l is a side View of a floor nailingmachine embodied by'the present invention.

Fig. 2 is a front elevation of the same.

Fig.3 is a view'of that side of the machinehpposite the side shown in Fig. 1.-

Fig.4 isa iragmental top view of parts, .showing the nail feed channel and the nail release device for dropping the nails, one at a time, for delivery to the hammer ordriving'mechanism.

Fig. 5 is a View 'of the parts seen in Fig. 4, showing their position after being actuated: for dropping a nail.

.F'ighfi is a detail, in side elevation, particularly of those parts of 'the mechanism whereby the intermittent and varied :advance movements of the machine are eiie'cted.

Fig. 7 is a dtail of'the ball clutch ratchet mechanism used with the devices ,f-oradvancing the machine across a'IfiOOI'.

Fig. 81s a longitudinal sectional view ofth'e hammer guide and nail holdezt Fig. 9' is a sectional detail of :the nail supply hopper and apart of the nail delivery channel.

Fig. 10 is a detail of the mechanism for actuating the caster truck to lift the 'machineclear of the floor.

Fig. 11 is a sectional detail of the driving clutch betw-ee'nthe motor shaft and driving gears.

Fig. 12 is an upper end View of the nail driving hammer and hammer guide bracket.

Figxlliis a sectional detail of the receivingend portion ofthe nailguide tube and its mounting block.

Fig. l -l is a sidev view of parts showingthedisposition of the nail feed mechanism relative to its actuating means. A

The present machineis designed, upon being initially setin place and started, to move under its own power straight across an area on which floor boards have been placed in position for nail- The travel is effected in a succession of intermittent movements, and a nail is driven after'each advancement and While the machine is at rest. Also, provisionis made that for the nailing of flooring of the usual widths, the advance movements shall alternately be long and short, so that the nails maybe driven through each board ciose to its opposite edges; the nails that are driven next to the adjacent edges of adjacent boards being relatively closely spaced, and t'heinterval between them is herein referred to as short, while nails that are driven through the opposite edges of the same board are spaced farther apart, and this is herein referr'edto as the long interval.

Provision is also made that during each ad- Vance movement, a nail will be admitted to the nannomer of the driving shoe, the hammer lifted, and when the advance movement stops, the hammer is forcibly actuated to drive the nail; then there is another advance movement. With each advancement, another nail is dropped and the hammer is reset, and this operation continues until the machine is stopped.

Referring more in detail to the drawings- The machine, in its present preferred form, comprises a horizontally disposed, rectangular base Ill, supported across its forward and rearward ends by parallel rollers II and i2 of substantial length. These rollers have trunnions i3 extending from their ends revolubly mounted in bearings l4 that are fixed to the under side of the base If] adjacent its corners, as noted best in Fig. 3. Preferably, the supporting rollers are equipped with slightly enlarged tires l2 at their ends to better insure straight travel in rolling on a floor that may be slightly uneven.

Mounted rigidly on the base is a vertical bracket l5 which rigidly supports a gear box it upon its upper end. Mounted upon the gear box is a nail supply hopper I! from which the nails for securing the floor are delivered, by means presently described in detail, to the nail holder for driving by the hammer. The hopper is shown to be equipped with a cover IIc that is hingedly attached, as at I8.

The means powering the machine for effecting its travel and the movement of the various parts, comprises an electric motor that is fixed on the base [0 below the gear box It and rearwardly of the bracket 15. Th motor shaft 2| is axially alined with a drive shaft 22 that is revolubly mounted in the gear box 16 in bearings 23 and 23. The lower end of shaft 22 may be operatively con- 'rlected with and released from the motor shaft 2i through the mediacy of a releasable clutch device, indicated generally in Fig. 1 at 24, later more fully described.

On shaft 22, as seen in Fig. l, is a worm gear 25 which drives a gear 26 that is fixed on a horizontal shaft 21 that extends through and is revolubly mounted in the gear box IE. Fixed on one end of the shaft 21, at the outside of the gear box, is a crank arm 28. On the other end of the shaft, at the outside of the gear box, is a belt pulley 30, best seen in Fig. 3, over which a belt 3| operates to drive a pulley 32 that is fixed on a shaft 33 extending horizontally. through the nail picker housing H.

In Fig. 9, it is noted that the nail picker housing forms a cylindrically shaped enclosure and that the shaft 33 is coaxial thereof. It is also therein noted that the shaft 33 is equipped with short radial arms 34 designed to keep the supply of nails in the housing in a stirred up condition and that there are two arms, designated by reference character 34, longer than the others, having outer end portions adapted to mOVe along a slot 35 in the hopper base. This slot leads upwardly along the forward side of the housing into a downwardly inclined channel or guide slot 38 which is formed between two parallel, slightly spaced bars 3939 which are best shown in Figs. 4 and 5. The slots 35 and 38 are of such predetermined width that the heads of the nails will not pass through and therefore the nails that are brought into the slot by the action of the arms 34' will be suspended by their heads in the channel, and will form in a row as seen in Figs. 1 and 2. The row of nails held in the downwardly inclined channel 38 will advance by gravity to the lower end thereof and there provision is made whereby they will be individually delivered into the PP R end of a tube 45 that leads downwardly, as noted in Fig. 2, to the hammer guide 4! wherein they are delivered to the nail holder shoe 42 for driving by the hammer.

Referring now more particularly to Figs. 1 and 8, it will be observed that the hammer guide 4| comprises a vertical tubular member terminating at its lower end in a squared block-like portion 4la which is formed as an integral part of the base ill at a forward side corner thereof. Continuing upwardly from the block 41a is an elongated cylindrical standard 411). An axial bore 43 is formed the full length of the parts Ma and Mb. The lower face of the block 4Ia is somewhat above the floor level, as seen in Fig. 6, and the shoe 42, having a rounded under surface to facilitate easy sliding on the floor, is disposed between the block and floor. This shoe has a Vertical stem portion 45 slidably contained in the lower end of the bore 43 and formed through the shoe, and its stem is an axial bore 46 that opens upwardly into the bore 43 with a conical flare as at 43'. With the travel of the machine across a floor, the shoe 42 rides on the floor surface and the guide stem 45 moves up or down in the bore 43 as may be required to meet slight surface variations.

The nail delivery tube 40 enters the block 4la above the upper end of the shoe guide stem, as will be noted in Fig. 8, and nails delivered through the tube, will enter point first into channel 43 when the hammer is retracted, and will drop into the shoe channel 45 and will come to rest against the floor.

The hammer used in the machine for driving the nails comprises a heavy, tubular body portion 5!! that is telescopically slidable on the upper end portion of the hammer guide tube 4%. Fixed in the upper end of the body 50, as best shown in Fig. 8, is a nail driving rod or plunger 52 that is slidably contained in the bore 43. At its lower end, the rod 52 has a portion of reduced diameter, designated at 52a, set off by a downwardly facing tapered shoulder 53. The reduced porj tion 52a is adapted to enter the shoe stem channel to engage the nail head for driving the nail. The shoulder 53 will engage the flared upper end portion of channel 44 of the shoe to limit the downward travel of the hammer.

By reason of the fact that the shoe 42 always rides on the floor surface, and the provision of the conically tapered seat 46 in the upper end of the channel 46 on the stem 45 of the shoe, and the limiting of the downward drive of the hammer by the shoulder 53 of rod 52 engaging in the seat 46, the nails will all be uniformly driven and their heads equally set below the surface of the board.

The driving force of the hammer is effected by a pair of coil-ed springs 55 and 55 that have their lower end hooks attached to pins 56 extended from the opposite sides of the block Ma and which have upper end hooks attached to lugs 51 on the under side of a crosshead member 53 on the body 50 as shown in Fig. l. The hammer is lifted against the tension of these springs through the mediacy of the lever arm 28 incident to its rotation by shaft 21.

By reference to Fig. 12, it will be observed that the cross head portion 58 of the hammer body 53 has vertical keys to at one edge thereof that are slidably contained in vertical keyways ti formed in a bracket 52 that is fixed to the forward face of the gear box [6. This sliding'consteam ne'ction retains the hammer' ag'ainst rotationon its guide memb r as it movesup or down.

Itis alsotobe noted,in Fig. 6, that the crosshead 58 has a flat horizontal urrd'er s'ui fa'ce'fiii extending in a front to rear direction relative to the travel of the machine and onset inwardly from the hammer axis.

On the outer end "of the crank arfn 28, that isfixed to the driven shaft 21, is a roller 63 that,

during each rotation of the crank arm 2 8,-en"- gages the surface 58" and effects the lifting of the hammer body, thus to place the springs 55 under tension. In Fig. 6, the 'position of the the crosshead to lift the hammer, is designated by the dotted circle 63d. The upward swing or the crank arm, then lifts the'h'ammer. Thedirec tion of rotation is indicated by the arrow in hammer was raised. Theposition of the hammer in its lowered driving position'is shown in Fig. 6, and the nail head is'seen as being set below the floor surface. in Fig. 8, the hammeris seen in a raised position.

The nail driving operation, in each instance,

takes place while the machine is at rest. However, before the driving of each nail, the "machine is advanced its proper interval for spacing the nails in a row. By referenceto Fig. 6,

it will be understood that when nails are driven closeto the opposite edges of each board, the advance movements for such nailingwould necessarily be alternately short and long. The

roller at the time when it first engages with which it is shown inwFig. 6, to the substan tially vertical dotted line position, designated at Mb.- With'th'e swinging of the lever M through this-arc, the link ll causes a rotative advancemerit of the ratchet disk 10 that turns the roller i-2 accordingly, and moves the machine forwardly a definite distance. In this instance, it is the interval-for long spacing. It will be understood that this advance movement takes place while the haminer is being raised and is completed just before the hammer is released 'by the passing of roller 53 from the surface 58. To 'br i ng about the short'interval of advancement, alternately with the long intervals, I have provided the following mechanism.

With each upward swing of-the lever arm 14 through the are which has been designated by the double pointed arrow 0: in Fig. 6, a spring pressed pawl 89, pivoted on the lever i i, engages W'itl-f atooth or point at a four-pointed star wheel 81 that is retat'ably supported on a side surface orthe-base-m as shown in Figs. 1 and 6. This contactwill advance the starwheel one-quarter turn. Fi xed'to the star wheel, to turn therewith, is a can 82- withequally" extending rises 82' at diametrically opposite sides thereof. Rotatably mounted along that same edge of the base it, on

, which the star wheel is located, in bearings 83 short distances would beabout one-half inch.

The "long distances would be equal to the width of the board less the short distance. Due to this variation in distances, provisidn has been made herein for an automatic control of the advance movements to take care of this requirement that alternate advance movements be long and short. This mechanism now' bra-described.

Mounted on the end of the roller I2 is a ratchet, ball clutch disk 10. This is revoluble axially of the roller trunnion and with each rotative movement thereof in a forward direction; that is, clockwise in Fig. 6, the roller i2 is rotated accordingly to advance the machine. A link H has one end thereof pivotally connectcd to the disk, eccentrically thereof, as at l2 and 113.5155 other end pivotally connected, by pivot bolt 13, to a lever arm l4. Thearm M liesalong one edge of the base Hl' and has "one end pivotally fixed thereto'as at 15, and at its other end is operatively connected by meansbf,

an upwardly directed rod 16 and a guide block 17 with the lever arm 28'." The rod TB-slides through a hole Tl in the guideblock'and at its upper end has a nut 48 applied thereto to limit the extent of this sliding movement and to effect a holding connection through which the lever arm M can be actuated by the crank arm 28.

With each rotation of the shaft 2'! and the crank arm 28, the connecting rod 16 will cause an osci lating movement of the lever arm 14,; for example, moving it from the fill! line position and 83, is a horizontal shaft 84 having a lateranymmed'ess portion tethat is so located and so extends that it may" be engaged by theparts 82" of the cam itsrotatiVe advancement. A

s'topwarfh =36 extends radially from the shaft 84- in the same plane as the part 35. The cam 82 isso related td'the shaft 84 that when a part 82 "thereof is rotated into contact with the laterally turned shaft end 3-5, it rotates the shaft 34 to a position at which the stop arm 86 will. extend upwardly, as in Fig. 6 and, at such position, will be out of the plane of travel of the lever arm 14. When the lever arm '14 swings upwardly from its full line position in Fig. 6, and the pawl 8i! engages the star wheel to advance the cam to disengage the part 85, the shaft M will then be allowed to rotate backand the stop arm d6 swings therewith to a substantially horizontal position at which it extendsin the path of return travel of lever arm it,- so that it will then act to prevent the complete return movement of this lever arm to "that position shown in dotted lines l lo:

in Fig. 6. This limits the full return of the ratchet clutch disk "if! accordingly and shortens the arcof travel of lever M so that the next ad- Vance movement of the machine will he only that made possible by the travel of the lever arm 74 through the are indicated by the double pointed arrow 2) shown in Fig. 6. This results in the shoiffiiiiterval of advancement of the ma- By reason of the cam action, alternate advance: movements will be long and short.

rotary or change the long interval. of advancement, the point of attachment of the link 'N Witt-i the lever arm it may be changed closer toe: arther from the pivot point '55; this being possibledue to thefact that bolt i3 is held in a slot that is longitudinally of the lever M and may be adjusted therealong. Or the extent of return of the lever is maybe changed by the setting of a stop 8l in a horizontal slot 8'8 in a plate 89 to the bas'e H].

To vary the short interval of advance, the arm stmay be adjusted to different positions along the-shaft 84 so that the return travel of the lever arm '14 controlled thereby may be made more or less. For holding any adjustment of the arm 66, it is provided with a set screw 86' that may be tightened against its mounting shaft. A small coiled spring 845 is applied about shaft 84 and is attached at one end to the base and at its other end to the shaft to urge it rotatably in a direction to cause the part 85 to lie in the path of cam 82.

The ratchet clutch mechanism connecting the disk It with the roller I2 is illustrated best in Fig. '7 wherein it is seen that disk lil is rotatably on the end hub Bil of roller I2 and has a one-way driving connection with the hub effected through the mediacy of a ball clutch mechanism of common type herein designated at 92.

The roller I2 is equipped with a friction brake mechanism designated at 93 that prevents free turning of the roller and overcomes any tendency of the machine to roll after an advance movement has been completed.

The operation of the nail picker mechanism, shown in Figs. 4 and 5, is synchronized with the advance movement of the machine so that immediately following each nail driving action of the hammer, a nail is discharged from the channel 38 into the nail delivery tube 40. The nail moves by gravity in the tube to the block 1 Ia, and when the hammer is lifted, it drops into the channel 43 of the block and from there passes into the mounting stem of the shoe 2. The row of nails supplied from the hopper and held in the guide channel 38 feeds downwardly as the nails are successively removed from the lower end of the channel and the channel is kept filled by the picker arm.

In Fig. 4, it is shown that the end of the channel 38 is closed by a cross slide I carried in a bearing IOI that is formed as part of a block I02 fixed to the lower end guide bar 39' as noted in Fig. 4. Located about one end of the slide is a coil spring 503 held under compression and engaged at one end against the adjacent bearing WI and at its other end against a washer I04 fixed to the shaft end by screw I05. The spring yieldingly retains the slide in its retracted position at which a notch I06, formed in a side surface of the slide, as noted in Fig. 4, registers with the lower end of the nail channel I38. The notch is of such depth that it will contain one nail only at a time therein. To discharge the nail from the notch to the delivery tube 40, the slide is actuated endwise to a distance that will move the notch into registration with a downwardly tapered pocket It? formed in a block I08 that is fixed to the inner face of the bracket 62. The nail delivery tube 40, as noted in Fig. 8, connects with the lower end of this pocket and leads therefrom to the hammer guide Ma. A finger I09 is fixed to the channel side bar 39 and this extends into the path of travel of the nail head when the slide is actuated endwise, thus to cause the nail to be moved out of the notch I06 and dropped into the pocket I01.

The means for actuating the slide I 00 in proper timing with the machine operations is shown in Figs. 1, 16, 14 and 15. Here it is shown that a lever I I is pivotally mounted as at I I6 by a bracket I If attached to a side wall of gear box I6. One end of the lever has an operating connection, as seen in Figs. 4 and 5 at HQ, with the slide I00. The other end of the lever is curved to an extent that it will lie in the path of travel of the crank arm 28 as it swings across the top of its arc of travel, and will be engaged by the arm just after the hammer has been dropped, and so actuated thereby as to shift the slide I00 endwise and drop 8 a nail into the tube 40. When lever H5 is disengaged by the crank arm, the slide is returned by spring I03 to position for receiving another nail into notch I06.

The driving clutch mechanism that connects the motor shaft H with the drive shaft 22, as seen in Fig. 11, comprises a friction cone I20 fixed on the motor shaft and a complemental friction head I25 keyed on the drive shaft. The friction head is adapted to be shifted up and down on the shaft 22 to engage or disengage the friction cone, and this is here accomplished by a lever I26 having one end pivoted to the bracket I5 as at I21 in Fig. 3, and having a ball bearing connection I30 with the hub portion of the friction head through which the latter may be held in driving contact with the cone.

To hold the clutch set, a latch lever I40, pivoted at its upper end on a bracket MI attached to box I6, depends across the free end of lever I26. This latch lever has a notch M2 (Fig l) in which a stud I43 on the lever may be seated to hold the clutch engaged. To release the drive, the latch is disengaged and a spring I45, attached to lever I26 and to the bracket MI, lifts the clutch friction head free of the driving cone.

In order that the machine may be automatically stopped after advancing across an area, I provide a horizontal push rod I50, guided slidably in a guide block I55 at the forward side of the machine, and attached pivotally at its other end to the latch lever I40. At the forward end of the rod is a knob I52 designed to engage with a wall or abutment to disengage the latch, thus to automatically stop the operation when a room has been traversed.

In order that the machine. when not being used, may be rolled freely on a fioor, I provide a supporting carriage I60 therefor, equipped with corner casters I6. This carriage is mounted on the underside of base I0 between the rollers II and I2, and it has longitudinal inclined side rails I63 engaged with similarly inclined rails I'64 formed on a frame I65 that is applied to the under side of the base frame Ill. The carriage I60 is held by vertical bolts I66 against longitudinal movement relative to base I0, but may raise or lower on the bolts. Springs I61 applied about the lower ends of the bolts, urge the carriage to raised position. The frame IE5 is longitudinally adjustable relative to the base and, by this movement. will cause the caster frame to be pushed downward from the base to lift the machine.

The shifting of the frame I65 is eifected by means of a hand lever I'l0 fixed on a shaft III that is rotatably mounted just forward of bracket I'5 to extend down through the base I0. At its lower end, the shaft III has a crank pin I12 fixed thereon to engage the frame I65 in a manner whereby the turning of the shaft will shift it in one direction or the other as required to raise or lower the machine; this being due to the location of the inclined rails IE3 and I'M provided respectively on the carriage and frame.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent isl. A floor nailing machine comprising a base, rollers supporting said base for its straight line travel across a floor, a motor on the base, a shaft continuously driven by the motor, a clutch operable by the driven shaft to drive one of the rollers to cause intermittent advance movements of the base across a floor and means to cause the clutch to eifect movements of alternate short and long intervals of definite length, nail driving means on the base, and devices operated by said driven shaft to effect a nail driving operation following each advance movement of the base.

2. A floor nailing machine comprising a base, rollers supporting said base for straight line travel across a floor, a motor on the base, a shaft continuously driven by the motor, a crank arm rotated by the shaft, a one-way clutch disk associated with one of the rollers, and linkage actuacted by said crank arm and connected with said disk to effect oscillating action thereof whereby the roller is caused to intermittently advance the base across a floor, nail driving devices on the base, and actuated by the crank arm in timing with the advance movements of the base to drive a nail into the floor after each advance movement thereof.

3. A floor nailing machine comprising a base, rollers supporting said base for straight line travel across a floor, a motor on the base, a shaft continuously driven by the motor, a lever pivoted on the base, and means connecting said lever with the driven shaft to cause the lever to be oscillated in a forward and reverse direction and in accordance with rotation of the shaft, a one-way driving clutch associated with one of the rollers, a link connecting the oscillating lever and clutch for the actuation of the latter to elfect a definite advance movement of the machine across the floor to be nailed, with each advance swing of the lever, a nail driving device on the base and operated under control of the rotating shaft and in timing with the advance movements of the base.

4. A floor nailing machine as recited in claim 3 wherein means is operatively associated with said pivoted lever and actuated thereby to shorten alternate return movements of the oscillating lever, thus to shorten alternate advance movements of the machine accordingly.

5. A floor nailing machine comprising a base, rollers supporting said base for straight line travel across a floor, a motor on the base, a shaft adapted to be continuously driven by the motor, a lever arm pivoted on the base for oscillation, a crank arm on the shaft, a link operatively connecting the crank arm and lever to actuate the latter with forward and return oscillating action,

a one-way driving clutch device associated with one of the rollers, a link operatively connecting the oscillating lever and clutch device for effecting advance movements of the machine with the forward swinging actions of the lever, a movable stop device mounted on the base and adapted to be engaged with the lever to shorten its normal return travel, and a, stop control mechanism that is actuated by the successive oscillations of the lever to move the stop device into and from functional position to shorten alternate return movements of the lever, thereby to effect the shortening of alternate advance movements of the machine as efiected through the clutch device.

6. A nail driving machine comprising a base frame, rollers mounting said base for straight line travel across a floor, a rotatably driven shaft on the base frame, a hammer guide, a spring loaded hammer mounted thereon, a nail holding means associated with the hammer guide, nail delivery means for the feeding of nails to said nail holding means, an over-running clutch associated with one of said rollers, a crank arm fixed to the said shaft, and devices operated by the crank arm during each rotation thereof to actuate the clutch to effect a definite advance movement of the machine, means actuated by the crank to lift the hammer, means to release a nail to the holding means, and means to release the hammer to cause said nail to be driven.

DANIEL J. DOUGHERTY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 924,054 Gehne June 8, 1909 1,060,377 Stutzer Apr. 29, 1913 1,171,685 York Feb. 15, 1916 1,693,290 Fawcett Oct. 3, 1928 2,306,627 Johanssen Dec. 29, 1942 FOREIGN PATENTS Number Country Date 913 Great Britain Jan. 14, 1907 

